Creating a 10km wireless bridge...pointers?

[Modulok]

List,

I have been tasked with getting a DSL connection across about 10km of
no-man's-land to a rural location without internet access. Ideally,
all traffic inbetween the two directional antennas would be encrypted.
(Nice, but not entirely required.) 3Mb/s would be great! Something
like:

LAN<->BSDrouter<->modem<->Antenna<~~air~~>Antenna<->modem<->DSL

I'm looking for general pointers of both hardware and software to
achieve this. I'd like to employ FreeBSD as much as is feasible. This
is my first WAN network project, so even newbie pointers and general
references would be much appreciated. (Hardware suggestions, books to
read, etc.) Reliability is of mild concern, simply because I don't
want to drive 10km at 3:00am when something breaks.

Tips? References? Advice?
-Modulok-